1. Field of the Invention
The present invention relates to a shell of a small-sized marine craft for use in marine sports or for leisure purposes, which is suited to running about the sea area near the shore under the control of a rider on the stern portion of the shell who grips a handle bar standing up from the bow portion of the shell. More particularly, the invention is concerned with the shape of the shell of such marine craft of the type mentioned above.
2. Description of the Related Art
In general, a small-sized marine craft of the kind described has an engine mounted in an engine room formed in the bow portion of the shell and a propulsion means provided at the stern portion of the same. The rider stands up or sits on a deck portion formed on the shell to the rear of the engine room and grips the steering handle bar on the bow portion of the shell.
The shell has a breadth which is substantially equal to or slightly greater than the shoulder breadth of a rider.
The propulsion means may be a propeller or a pumped water jet. Where a pumped water jet is used, the marine craft can be steered by changing the direction of the jet.
This type of marine craft is generally light in weight and has an excellent running performance. For instance, it can run at a considerably high speed of 50 km/h or so. Thus, the running performance is largely affected by the shape of the shell.
In known marine craft of the type described, the shell is usually composed of two parts: namely, a deck constituting the upper part of the shell and a hull constituting the bottom of the shell. The deck and the hull are provided with substantially flat joint surfaces extending from the bow to the stern and are jointed together at these joint surfaces such that the deck and the hull together present a smooth outer side surface of the shell with no projection. Alternatively, the joint surfaces are extended horizontally outwardly to provide joint flanges which project laterally from the shell side when the deck and the hull are jointed together.
A continuous smooth side surface of the shell, however, imposes a problem in that the water tends to flood the deck and invades the air inlet of the engine or the space in the shell when the marine craft turns sharply or when the sea is rather rough. Flooding of the deck by water cannot be completely prevented even when the shell has a jointing flange projecting laterally therefrom. Use of a jointing flange, in addition, produces another problem in that water rising up to the bow portion of the marine craft during running acts to develop a downward force on the flange portion around the bow such as to cause a moment which depresses the bow, often resulting in an accidental stall in a halfsubmerged state.
In order to avoid such an accidental stall, it has been proposed that the length of the shell be increased such as to allow effective use of the buoyance at the bow portion of the shell. This countermeasure, however, runs against the demand for reduction in the size and weight of the marine craft of the kind described, and makes it difficult to improve the running performance.